1. 
   SUB-FLOOR
   Material (such as particleboard) installed before finish flooring materials.
   Found op http://www.proofrock.com/glossary.html
   
   
2. 
   Subfloor
   Boards or plywood laid on joists over which a finish floor is to be laid.
   Found op http://www.rookinspections.com/glossary/glossarys.shtml
   
   
3. 
   Subfloor
   - The framing components of a floor to include the sill plate, floor joists, and deck sheeting over which a finish floor is to be laid.
   Found op http://www.homebuildingmanual.com/Glossary.htm
   
   

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